Lens moving mechanism

ABSTRACT

A lens moving mechanism includes a first lens guide unit which guides a lens mount, on which a lens for projecting light is mounted, in two orthogonal axis directions among three orthogonal axis directions including an optical axis direction of the light. The first lens guide unit includes a first track rail and a second track rail which are disposed to intersect each other in the two orthogonal axis directions, and one or a plurality of slider blocks which are mounted to be relatively movable on both or either of the first track rail and the second track rail. The one or plurality of slider blocks are disposed at an intersecting portion between the first track rail and the second track rail in one axis direction orthogonal to the two orthogonal axis directions, or are disposed to at least partially overlap each other in the one axis direction.

TECHNICAL FIELD

The present invention relates to a lens moving mechanism.

Priority is claimed on Japanese Patent Application No. 2016-213675 filedOct. 31, 2016, the content of which is incorporated herein by reference.

BACKGROUND ART

Conventionally, a projector including an optical device that includesthree light modulating devices (liquid crystal panels) which modulateeach of the three colors of light R, G, and B according to imageinformation and a color synthesizing optical device (a cross dichroicprism) to which these light modulating devices are provided and whichcombines the three modulated light fluxes to form image light, and aprojection optical device (a projection lens) that magnifies andprojects the thus formed image light, is known.

This projector includes a lens moving mechanism that moves a projectedimage vertically and horizontally, and performs focus adjustment or thelike without moving a projector main body. Patent Literature 1 belowdiscloses a projector including a position adjusting unit that adjusts aposition in the three X, Y, and Z orthogonal directions. This positionadjusting unit includes a base portion which moves in the Z axisdirection relative to a pedestal, a leg portion which moves in the Xaxis direction relative to the base portion, and a connection portionwhich moves in the Y axis direction relative to the leg portion (seeFIG. 5 of Patent Literature 1).

CITATION LIST Patent Literature

[Patent Literature 1] Japanese Unexamined Patent Application, FirstPublication No. 2007-286121

SUMMARY OF INVENTION Technical Problem

In recent years, in large projectors, the weight of a lens hasincreased, and a lens moving mechanism has been required to have lowweight and high rigidity. For this reason, for example, it isconceivable to form a frame constituting the lens moving mechanism usinga lightweight aluminum cast product and to mount a highly rigid linearmotion guide device configured by a track body and a moving body on theframe. However, there is a possibility that bending will occur due tothe difference in rigidity between the frame and the linear motion guidedevice even if a linear motion guide device of an appropriate size isselected.

The present invention provides a lens moving mechanism which can inhibitan occurrence of bending and which is lightweight and has high rigidity.

Solution to Problem

According to the first aspect of the present invention, a lens movingmechanism includes a lens mount unit on which a lens for projectinglight is mounted, and a lens guide unit which supports the lens mountunit and guides the lens mount unit in two orthogonal axis directionsamong three orthogonal axis directions including an optical axisdirection of the light. The lens guide unit includes a first track bodyand a second track body which are disposed to intersect each other inthe two orthogonal axis directions, and one or a plurality of movingbodies which are mounted to be relatively movable on both or either ofthe first track body and the second track body. The one or plurality ofmoving bodies are disposed at an intersecting portion between the firsttrack body and the second track body in one axis direction orthogonal tothe two orthogonal axis directions or are disposed to at least partiallyoverlap each other in the one axis direction.

According to the second aspect of the present invention, the lens guideunit includes a first moving body mounted to be relatively movable alongthe first track body, and a second moving body mounted to be relativelymovable along the second track body. The first moving body and thesecond moving body are relatively movable within a range in which theyat least partially overlap each other in the one axis direction.

The first moving body and the second moving body may be relativelymovable within a range in which an area overlapping in the one axisdirection does not change.

According to the third aspect of the present invention, the lens guideunit includes a support member which supports the lens mount unit, anintermediate member to which the second track body is fixed and whichsupports the support member via the second moving body, and a fixingmember to which the first track body is fixed and which supports theintermediate member via the first moving body and is fixed to a mountingobject.

The first moving body, the second moving body, the first track body, andthe second track body may have a Young's modulus greater than that ofthe supporting member, the intermediate member, and the fixing member.

According to the fourth aspect of the present invention, the firstmoving body has a plurality of moving body fixing holes for fixing theintermediate member, the second track body has a plurality of track bodyfixing holes for fixing the second track body to the intermediatemember, and the plurality of moving body fixing holes of the firstmoving body are alternately disposed with the plurality of the trackbody fixing holes of the second track body along the second track bodywhen viewed in the one axis direction.

The lens guide unit may support the lens mount unit via a second lensguide unit which guides the lens mount unit in the one axis direction.

The one axis direction may be a vertical direction.

According to the above-described aspects, an occurrence of bending canbe inhibited and a lightweight and highly rigid lens moving mechanismcan be obtained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view showing a lens moving mechanism according to anembodiment of the present invention.

FIG. 2 is a side view showing the lens moving mechanism according to theembodiment of the present invention.

FIG. 3 is a configuration diagram showing a linear motion guide deviceaccording to the embodiment of the present invention.

FIG. 4 is a perspective view showing an arrangement of linear motionguide devices in a first lens guide unit according to the embodiment ofthe present invention.

FIG. 5 is a plan view showing a base member to which a first linearmotion guide device according to the embodiment of the present inventionis fixed.

FIG. 6 is a plan view showing a saddle member to which a second linearmotion guide device according to the embodiment of the present inventionis fixed.

FIG. 7 is a cross-sectional view taken along a line A-A shown in FIG. 6.

FIG. 8 is a plan view showing the relationship between a movable rangeof a first slider block and a movable range of a second slider blockaccording to the embodiment of the present invention.

FIG. 9 is a front view showing an arrangement of the linear motion guidedevice in a second lens guide unit according to the embodiment of thepresent invention.

FIG. 10 is a plan view showing the relationship between a movable rangeof a first slider block and a movable range of a second slider blockaccording to a modified example of the embodiment of the presentinvention.

FIG. 11 is a perspective view showing an arrangement of a linear motionguide device in a first lens guide unit according to a modified exampleof the embodiment of the present invention.

FIG. 12 is a plan view showing a base member according to a modifiedexample of the embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the drawings. It should be understood that, in order toallow better understanding of the gist of the invention, the followingembodiments are explained by way of examples and do not limit thepresent invention unless otherwise specified. In the drawings used forthe following description, in order to make features of the presentinvention easy to understand, main parts may be enlarged for convenienceand the dimensional ratios between respective components may notnecessarily be the same as the actual ones. In addition, for the sake ofeasy understanding of the features of the present invention, thedrawings used for the following description may have omitted parts forconvenience.

FIG. 1 is a front view showing a lens moving mechanism 1 according to anembodiment of the present invention. FIG. 2 is a side view showing thelens moving mechanism 1 according to the embodiment of the presentinvention.

As shown in FIG. 2, the lens moving mechanism 1 includes a lens mount 2(a lens mounting portion) on which a lens 100 for projecting light ismounted, a lens shift unit 3 which supports the lens mount 2 and guidesthe lens mount 2 in three orthogonal axis directions including anoptical axis direction in which an optical axis 101 of the lightextends.

Also, in the following description, an XYZ orthogonal coordinate systemis set, and the positional relationship between respective members maybe described with reference to the XYZ orthogonal coordinate system. TheY axis direction is the optical axis direction, the X axis direction isan orthogonal-to-optical axis direction (a horizontal direction)orthogonal to the optical axis direction, and the Z axis direction is avertical direction (one axis direction) orthogonal to the X and Y axisdirections.

As shown in FIG. 1, the lens mount 2 includes a main body portion 10formed in an annular shape, an edge portion 11 provided along an outercircumferential edge of the main body portion 10, and a back surfaceportion 12 provided on a back surface side of the main body portion 10,as shown in FIG. 2. As shown in FIG. 1, the main body portion 10 is adisk member having a mounting hole 10 a formed in a central portionthereof. As shown in FIG. 2, the edge portion 11 is a cylindrical memberprovided on a front surface side of the main body portion 10 andprotrudes forward from the outer circumferential edge of the main bodyportion 10 at a predetermined height.

As shown in FIG. 2, the lens 100 is mounted in a mounting hole 10 a. Thelens 100 is, for example, a lens barrel that accommodates a projectionlens and the like, and is fixed to the main body portion 10 usingfitting portions (not shown), bolts, or the like. The back surfaceportion 12 is a frame-shaped member provided on the back surface side ofthe main body portion 10, and is connected to a mount guide unit 33 ofthe lens shift unit 3. A protruding portion 12 a protruding toward theback surface side of the main body portion 10 is provided on the backsurface portion 12. The protruding portion 12 a is connected to a mountdriving unit 43 of the lens shift unit 3.

As shown in FIG. 1, the lens shift unit 3 includes a first lens guideunit 3A (a lens guide unit) which guides the lens mount 2 in twoorthogonal axis directions of the X and Y axes among the threeorthogonal axis directions, and a second lens guide unit 3B which guidesthe lens mount 2 in the Z axis direction. This lens shift unit 3 isconfigured by a frame section 20, a guide section 30, and a drivingsection 40.

The frame section 20 includes a base member 21 (a fixing member) fixedto a mounting object, a saddle member 22 (an intermediate member)disposed above the base member 21, and a table member 23 (a supportmember) disposed above the saddle member 22. The frame section 20 of thepresent embodiment is made of a die-cast component manufactured byaluminum casting.

The guide section 30 includes a saddle guide unit 31 which guides thesaddle member 22 in the orthogonal-to-optical axis direction (X axisdirection) relative to the base member 21, a table guide unit 32 whichguides the table member 23 in the optical axis direction (Y axisdirection) relative to the saddle member 22, and a mount guide unit 33which guides the lens mount 2 in the vertical direction (Z axisdirection) relative to the table member 23. The guide section 30 of thepresent embodiment includes a linear motion guide device 60 made ofstainless steel which is provided with a track rail 61 (a track body)and a slider block 62 (a moving body). The size of the linear motionguide device 60 in each guide unit is the same (same product).

The driving section 40 includes a saddle driving unit 41 (see FIG. 2)which moves the saddle member 22 in the orthogonal-to-optical axisdirection (X axis direction) relative to the base member 21, a tabledriving unit 42 (see FIG. 1) which moves the table member 23 in theoptical axis direction (Y axis direction) relative to the saddle member22, and a mount driving unit 43 which moves the lens mount 2 in thevertical direction (Z axis direction) relative to the table member 23.The driving section 40 of the present embodiment includes a linearactuator in which a shaft 51 moves back and forth relative to a mainbody portion 50.

The base member 21 is a bottom plate member disposed at a bottom portionof the lens shift unit 3. The base member 21 supports the saddle member22, the table member 23, the guide section 30, the driving section 40,the lens mount 2, and the lens 100. The saddle member 22 is anintermediate member disposed between the base member 21 and the tablemember 23. The saddle member 22 supports the table member 23, the tableguide unit 32, the table driving unit 42, the lens mount 2, the mountguide unit 33, the mount driving unit 43, and the lens 100. The tablemember 23 is a member connected to the lens mount 2 disposed above thelens shift unit 3. The table member 23 supports the lens mount 2, themount guide unit 33, the mount driving unit 43, and the lens 100.

As shown in FIG. 1, the table member 23 includes a bottom portion 24supported by the table guide unit 32, a pair of first wall portions 25provided to stand upward from both sides in a width direction (X axisdirection) of the bottom portion 24, and a second wall portion 26disposed between the pair of first wall portions 25. The bottom portion24 is formed in a flat plate shape along the XY plane. As shown in FIG.2, the first wall portion 25 is formed in substantially an L-shape(substantially a right triangle shape) disposed to stand upward withrespect to the XY plane. A front surface 25 a of the first wall portion25 is a vertical surface (the XZ plane) with respect to the XY plane,and the mount guide unit 33 is mounted thereon. The lens mount 2 iscantilevered on the table member 23 via the mount guide unit 33.

The second wall portion 26 is disposed behind the front surface 25 a ofthe first wall portion 25. As shown in FIG. 1, the second wall portion26 connects the bottom portion 24 to the pair of first wall portions 25to increase the rigidity of the table member 23. A through hole 26 a isformed in a central portion of the second wall portion 26. The throughhole 26 a is formed in an elliptical shape larger than the mounting hole10 a of the lens mount 2. The major axis of the elliptical shape of thethrough hole 26 a is set in the vertical direction (Z axis direction),and is formed to avoid interference with the lens 100 mounted in themounting hole 10 a even when the lens mount 2 moves in the verticaldirection relative to the table member 23.

As shown in FIG. 1, a support member 23 b is connected to one sidesurface of the pair of first wall portions 25. The support member 23 bsupports the mount driving unit 43. The main body portion 50 of themount driving unit 43 is fixed to the support member 23 b so that theshaft 51 moves back and forth in the vertical direction (Z axisdirection). A tip of the shaft 51 is fixed to the protruding portion 12a of the lens mount 2. When the shaft 51 moves back and forth relativeto the main body portion 50, the lens mount 2 moves in the verticaldirection relative to the table member 23.

The main body portion 50 of the table driving unit 42 is fixed to thesaddle member 22. The main body portion 50 of the table driving unit 42is fixed to an upper surface of the saddle member 22 so that the shaft51 moves back and forth in the optical axis direction (Y axisdirection). A tip of the shaft 51 is fixed to a protruding portion 23 aprotruding from a lower surface of the table member 23. When the shaft51 moves back and forth relative to the main body portion 50, the tablemember 23 moves in the optical axis direction relative to the saddlemember 22.

As shown in FIG. 2, the main body portion 50 of the saddle driving unit41 is fixed to the base member 21. The main body portion 50 of thesaddle driving unit 41 is fixed to the base member 21 so that the shaft51 moves back and forth in the orthogonal-to-optical axis direction (Xaxis direction). A tip of the shaft 51 is fixed to a protruding portion22 a protruding from a lower surface of the saddle member 22. When theshaft 51 moves back and forth relative to the main body portion 50, thesaddle member 22 moves in the orthogonal-to-optical axis directionrelative to the base member 21.

FIG. 3 is a configuration diagram showing the linear motion guide device60 according to the embodiment of the present invention.

The linear motion guide device 60 includes the track rail 61 providedwith rolling element rolling grooves 63 along a longitudinal directionthereof, a slider block 62 provided with rolling element load rollinggrooves 64 facing the rolling element rolling grooves 63, and aplurality of balls 65 (rolling elements) disposed between the rollingelement rolling grooves 63 and the rolling element load rolling grooves64.

The track rail 61 is an elongated member having a substantiallyrectangular shape in cross section. The rolling element rolling groove63 is formed on an outer surface 61 b of the track rail 61 in the widthdirection (the horizontal direction on the page of FIG. 3) along thelongitudinal direction of the track rail 61 (the direction perpendicularto the page of FIG. 3). The rolling element rolling groove 63 isrecessed in substantially an arc shape with respect to the outer surface61 b. A pair of rolling element rolling grooves 63 are formed on leftand right sides of the track rail 61.

Fixing holes 66 (a track body fixing hole) to be fixed to the object(the base member 21, the saddle member 22, or the table member 23) areformed in the track rail 61. The fixing holes 66 are formed to penetratethe track rail 61 in a thickness direction thereof (the verticaldirection on the page of FIG. 3). A counter bore 66 a, which allowspositioning of a bolt 80 (see FIG. 4, which will be described later) forfixing the track rail 61 at a position lower than an upper surface 61 aof the track rail 61 shown in FIG. 3, is formed in the fixing holes 66.

The slider block 62 includes a block main body 67 and a lid body 68attached to the block main body 67. The block main body 67 has a railreceiving groove 69 for receiving the track rail 61. The rail receivinggroove 69 opens in a lower surface of the block main body 67. Fixingholes 70 (moving body fixing hole) for fixing the object (the saddlemember 22, the table member 23, or the lens mount 2) are formed in amounting surface 67 a which is an upper surface of the block main body67. The fixing holes 70 are formed at a predetermined depth in athickness direction of the block main body 67. The fixing hole 70 is ascrew hole, and a bolt 81 (see FIG. 7, which will be described later)for fixing the object is screwed thereinto.

The rolling element load rolling groove 64 facing the rolling elementrolling groove 63 of the track rail 61 is formed in the rail receivinggroove 69. The rolling element load rolling groove 64 is recessed in anarc shape with respect to an inner surface of the rail receiving groove69. A pair of rolling element load rolling grooves 64 are formed on leftand right sides of the slider block 62 to sandwich the track rail 61therebetween. The rolling element load rolling groove 64 faces therolling element rolling groove 63 of the track rail 61 to form a loadrolling element rolling path L1 for rolling the balls 65 in a loadedstate.

No-load rolling element rolling paths L2 are formed in the block mainbody 67. The no-load rolling element rolling path L2 is formed to passthrough the block main body 67 in the longitudinal direction. An innerdiameter of the no-load rolling element rolling path L2 is larger than aball diameter of the ball 65 and no load is applied to the ball 65. Apair of no-load rolling element rolling paths L2 are formed on left andright sides of the slider block 62 corresponding to the rolling elementload rolling groove 64 (the load rolling element rolling path L1).

The lid body 68 is attached to both end faces of the block main body 67(see FIG. 4, which will be described later).

Like the block main body 67, the lid body 68 has a rail receiving groove71 for receiving the track rail 61. In the lid body 68, rolling elementdirection change paths L3 are formed on opposing surfaces facing bothend faces of the block main body 67. Each of a pair of rolling elementdirection change paths L3 connects both ends of the load rolling elementrolling path L1 and the no-load rolling element rolling path L2 to forman endless circulation path L for the balls 65.

The endless circulation path L is configured by a pair of linearportions (the load rolling element rolling path L1 and the no-loadrolling element rolling path L2) extending in the longitudinal directionof the track rail 61, and a pair of semicircular arcuate curved portions(the rolling element direction change paths L3) connecting end portionsof the pair of linear portions. In the present embodiment, two loopedendless circulation paths L are formed to extend in parallel in thelongitudinal direction of the track rail 61 at intervals in the widthdirection of the track rail 61. Also, the linear motion guide device 60in which a total of four endless circulation paths L, two on each ofleft and right sides, are formed may be used. A finite stroke typelinear motion guide device in which the endless circulation path L isnot formed may be used for the linear motion guide device 60. In thisfinite stroke type linear motion guide device, a cage (a rolling elementholding member) is disposed between the rolling element rolling groove63 and the rolling element load rolling groove 64, and the balls 65 arerotatably held by ball holders provided in the cage.

The ball 65 intervenes between the track rail 61 and the slider block 62to smoothly move the slider block 62 with respect to the track rail 61.The ball 65 of the present embodiment is disposed in the endlesscirculation path L substantially without any gap therebetween andcirculates in the endless circulation path L.

FIG. 4 is a perspective view showing an arrangement of the linear motionguide devices 60 in the first lens guide unit 3A according to theembodiment of the present invention.

As shown in FIG. 4, the first lens guide unit 3A includes a plurality oflinear motion guide devices 60. The first lens guide unit 3A includes afirst linear motion guide device 60A disposed in theorthogonal-to-optical axis direction (X axis direction) and a secondlinear motion guide device 60B disposed along the optical axis direction(Y axis direction).

The first linear motion guide device 60A includes a first track rail 61A(a first track body) fixed to the base member 21, and a first sliderblock 62A (a first moving body) which supports the saddle member 22 andis provided to be relatively movable along the first track rail 61A. Aplurality of first linear motion guide devices 60A are providedcoaxially in the orthogonal-to-optical axis direction (X axisdirection), and at least a pair (four in total in this embodiment) offirst linear motion guide devices 60A are provided at intervals in theoptical axis direction (Y axis direction).

The second linear motion guide device 60B includes a second track rail61B (a second track body) fixed to the saddle member 22, and a secondslider block 62B (a second moving body) which supports the table member23 and is provided to be relatively movable along the second track rail61B. A plurality of second linear motion guide devices 60B are providedcoaxially in the optical axis direction (Y axis direction), and at leasta pair (four in total in this embodiment) of the second linear motionguide device 60B are provided at intervals in the orthogonal-to-opticalaxis direction (X axis direction).

The first track rail 61A and the second track rail 61B are disposed tocross each other along the two orthogonal axis directions of the X and Yaxes. A plurality of first track rails 61A fixed to the base member 21and a plurality of second track rails 61B fixed to the saddle member 22are disposed to form an overall shape of crossing parallel lines. Also,the track rails 61 disposed coaxially with each other may be in contactwith each other or may be disposed at intervals.

FIG. 5 is a plan view showing the base member 21 to which the firstlinear motion guide device 60A according to the embodiment of thepresent invention is fixed.

As shown in FIG. 5, the first track rail 61A of the first linear motionguide device 60A is fixed to the base member 21 in theorthogonal-to-optical axis direction (X axis direction). A plurality offixing holes 66 are provided on the track rail 61 at intervals in thelongitudinal direction. The fixing holes 66 of the present embodimentare formed at three positions in total in both longitudinal end portionsand a central portion of the track rail 61. The bolts 80 are disposed inthe fixing holes 66 of the first track rail 61A, and the first trackrail 61A is fixed to the base member 21 (fixing holes 21 b in FIG. 7,which will be described later) at three positions.

A plurality of fixing holes 70 are provided in the slider block 62 (thefirst slider block 62A) at intervals in the width direction (Y axisdirection). In the present embodiment, a pair of fixing holes 70 areformed in both left and right end portions of the slider block 62 in thewidth direction at two positions in total. These fixing holes 70 aredisposed in a central portion of the slider block 62 in the longitudinaldirection (the direction orthogonal to the width direction). The bolts81 (see FIG. 7, which will be described later) are screwed into thefixing holes 70 of the first slider block 62A, and the first sliderblock 62A is fixed to the saddle member 22 at two positions.

When the lens 100 is positioned at a home position, the first sliderblock 62A is positioned at a central portion of the first track rail 61Ain the longitudinal direction, as shown in FIG. 5. Here, the homeposition of the lens 100 means a position at which the lens movingmechanism 1 supports the lens 100 in a steady state (an originalposition of the lens 100). At this time, the position of the fixing hole70 formed in the first slider block 62A and the position of the fixinghole 66 formed in the central portion of the first track rail 61A in thelongitudinal direction coincide with each other in the longitudinaldirection of the first track rail 61A.

The first slider block 62A is relatively movable in a movable range R1along the first track rail 61A. The movable range R1 of the first sliderblock 62A is set by a movable stroke of the saddle driving unit 41 (seeFIG. 2) or a stopper (not shown). The rolling element rolling groove 63(see FIG. 3) is formed in the first track rail 61A along theorthogonal-to-optical axis direction (X axis direction). That is, in theendless circulation path L in the first linear motion guide device 60A,a pair of load rolling element rolling paths L1 are provided to extendin parallel in the orthogonal-to-optical axis direction (X axisdirection) at intervals in the optical axis direction (Y axisdirection).

FIG. 6 is a plan view showing the saddle member 22 to which the secondlinear motion guide device 60B according to the embodiment of thepresent invention is fixed.

As shown in FIG. 6, the second track rail 61B of the second linearmotion guide device 60B is fixed to the saddle member 22 in the opticalaxis direction (Y axis direction). The bolts 80 are disposed in thefixing holes 66 of the second track rail 61B, and the second track rail61B is fixed to the saddle member 22 at three positions. The fixing hole66 at a central portion of the second track rail 61B in the longitudinaldirection is disposed in the Z axis direction (one axis direction) tooverlap the fixing hole 66 at the central portion of the first trackrail 61A in the longitudinal direction.

Bolts (not shown) are screwed into the fixing holes 70 of the secondslider block 62B and the second slider block 62B is fixed to the tablemember 23 at two positions. When the lens 100 is positioned at the homeposition, the second slider block 62B is disposed at the central portionof the second track rail 61B in the longitudinal direction, as shown inFIG. 6. At this time, the position of the fixing hole 70 formed in thesecond slider block 62B and the position of the fixing hole 66 formed inthe central portion of the second track rail 61B in the longitudinaldirection coincide with each other in the longitudinal direction of thesecond track rail 61B.

When the lens 100 is positioned at the home position, the second sliderblock 62B is disposed to substantially entirely overlap the first sliderblock 62A in the Z axis direction (one axis direction). As shown in FIG.6, the plurality of fixing holes 70 of the first slider block 62A aredisposed alternately with the plurality of fixing holes 66 of the secondtrack rail 61B along the second track rail 61B when viewed in the Z axisdirection.

FIG. 7 is a cross-sectional view taken along a line A-A shown in FIG. 6.

As shown in FIG. 7, a plurality of first fixing holes 22 b forconnecting the saddle member 22 and the first slider block 62A and aplurality of second fixing holes 22 c for connecting the saddle member22 and the second track rail 61B are formed in the saddle member 22. Thebolts 81 are inserted into the first fixing holes 22 b. On the otherhand, the second fixing holes 22 c are screw holes and the bolts 80 arescrewed thereinto. The first fixing holes 22 b and the second fixingholes 22 c are alternately formed at intervals in the Y axis direction.In other words, the first fixing hole 22 b is disposed in spaces betweenthe second fixing holes 22 c.

In a mounting procedure, first, the saddle member 22 is fixed to thefirst slider blocks 62A via the bolts 81. Next, the second track rails61B are fixed to the saddle member 22 via the bolts 80 so as to closethe first fixing holes 22 b which are connected with the first sliderblocks 62A via the bolts 81. That is, the saddle member 22 is fixed tothe first slider blocks 62A immediately below the second track rails61B.

Returning to FIG. 6, the second slider block 62B is relatively movablewithin a movable range R2 along the second track rail 61B. The movablerange R2 of the second slider block 62B is set by a movable stroke ofthe table driving unit 42 (see FIG. 1) or a stopper (not shown). Themovable range R1 of the first slider block 62A and the movable range R2of the second slider block 62B are set within a range where at least apart of the first slider block 62A and the second slider block 62Boverlap in the Z axis direction.

FIG. 8 is a plan view showing the relationship between the movable rangeR1 of the first slider block 62A and the movable range R2 of the secondslider block 62B according to the embodiment of the present invention.

As shown in FIG. 8, when the first slider block 62A is moved to an endof the movable range R1 and the second slider block 62B is moved to anend of the movable range R2, the second slider block 62B overlaps thefirst slider block 62A in an area S. The area S shown in FIG. 8 is theminimum area where the first slider block 62A and the second sliderblock 62B overlap, and, in this embodiment, at least a part of anintersecting portion of the first track rail 61A and the second trackrail 61B is included.

Returning to FIG. 5, the base member 21 has fixing holes 21 a for fixingthe base member 21 to the mounting object (a projector main body 102shown in FIG. 7) at a position corresponding to the first linear motionguide device 60A. Here, the position corresponding to the first linearmotion guide device 60A includes the position at which the first linearmotion guide device 60A is fixed and a surrounding portion thereof. Theposition at which the first linear motion guide device 60A is fixed is aregion including immediately below the first track rail 61A andimmediately below the first slider block 62A. The surrounding portion ofthe first linear motion guide device 60A is a region not overlapping thefirst track rail 61A and the first slider block 62A, and is a regionhaving a predetermined distance from the first track rail 61A and thefirst slider block 62A. The range of the surrounding portion in theorthogonal-to-optical axis direction is defined by the movable range R1of the first slider block 62A. The range of the surrounding portion inthe optical axis direction may be defined by the movable range R2 of thesecond slider block 62B.

As shown in FIG. 5, the fixing holes 21 a of the present embodiment aredisposed at the surrounding portion of the first linear motion guidedevices 60A. Specifically, the fixing holes 21 a are positioned in thevicinity (a side) of the first slider blocks 62A not overlapping thefirst slider blocks 62A, and positioned at the central portions of thefirst track rails 61A in the longitudinal direction. Respective fixingholes 21 a formed at positions corresponding to the respective firstlinear motion guide devices 60A are disposed outside the pair of firstlinear motion guide devices 60A disposed at intervals in the opticalaxis direction. Bolts 82 are disposed in the fixing holes 21 a, and asshown in FIG. 7, the base member 21 is fixed to the projector main body102. Fixing holes 102 a into which the bolts 82 are screwed are formedin the projector main body 102.

FIG. 9 is a front view showing an arrangement of the linear motion guidedevice 60 in the second lens guide unit 3B according to the embodimentof the present invention.

As shown in FIG. 9, the second lens guide unit 3B includes a pluralityof linear motion guide devices 60. The second lens guide unit 3Bincludes a plurality of third linear motion guide devices 60C disposedalong the vertical direction (Z axis direction).

A third linear motion guide device 60C includes a third track rail 61Cfixed to the table member 23, and a third slider block 62C whichsupports the lens mount 2 and is mounted to be relatively movable alongthe third track rail 61C. The plurality of third linear motion guidedevices 60C are provided coaxially in the vertical direction (Z axisdirection), and at least a pair (a total of four in this embodiment) ofthird linear motion guide devices 60C are provided at intervals in theorthogonal-to-optical axis direction (X axis direction).

A plurality of third track rails 61C are coaxially disposed at intervalson the table member 23. Reinforcing portions 27 are provided between thethird track rails 61C coaxially adjacent to each other. The reinforcingportion 27 has abutting surfaces 27 a with which end faces 61 c of thethird track rails 61C coaxially adjacent to each other are brought incontact. The abutting surface 27 a is formed in a planar shape parallelto the XY plane. The reinforcing portion 27 is in contact with the endfaces 61 c of the third track rails 61C which are coaxially adjacent toeach other at intervals, and secures the rigidity therebetween.

As shown in FIG. 2, the reinforcing portion 27 is integrally formed withthe table member 23. That is, the reinforcing portion 27 is a protrudingportion manufactured integrally with the table member 23 by aluminumcasting. The reinforcing portion 27 protrudes from the front surface 25a of the first wall portion 25 to the front side. The reinforcingportion 27 is formed to have a height H1 relative to the front surface25 a. The height H1 is smaller than a height H2 from the front surface25 a to the upper surface 61 a of the third track rail 61C. The heightH2 is smaller than a height H3 from the front surface 25 a to themounting surface 67 a of the third slider block 62C.

The reinforcing portion 27 is formed in a rectangular block shape in afront view shown in FIG. 9. A width W1 of the reinforcing portion 27 islarger than a width W2 of the third track rail 61C and smaller than awidth W3 of the third slider block 62C. An outer surface 61 b of thethird track rail 61C is in contact with an abutting wall 23 c extendingin the vertical direction. The abutting wall 23 c is formed at a heightthat does not interfere with the third slider block 62C. The third trackrail 61C is positioned by two surfaces of the reinforcing portion 27 andthe abutting wall 23 c and is fixed to the table member 23.

Subsequently, operations of the lens moving mechanism 1 configured asdescribed above will be described.

The lens moving mechanism 1 supports the lens 100 on the lens mount 2 asshown in FIG. 2. The lens shift unit 3 supports the lens mount 2 in acantilever manner and receives the load of the lens 100 via the lensmount 2. As a result, a moment is generated around the bottom portion(base member 21) of the lens shift unit 3 so that the lens shift unit 3tends to rotate (tilt) toward the front side. That is, a pull-out loadthat tends to pull out the bolts 82 (see FIG. 7) for fixing the basemember 21 to the projector main body 102 acts thereon.

The lens 100 for large projectors is heavy and the frame section 20 ofthe lens shift unit 3 is easily bent. When the base member 21, thesaddle member 22 and the table member 23 are made of die-cast componentsmade by aluminum casting as in the present embodiment for the purpose ofweight reduction, this bending becomes larger. For this reason, in thepresent embodiment, the linear motion guide device 60 (the track rail61, the block main body 67, and the balls 65) made of stainless steelhaving a larger Young's modulus than the base member 21, the saddlemember 22 and the table member 23 is adopted to enhance the rigidity ofthe lens shift unit 3.

However, in the lens moving mechanism 1, most of the load of the lens100 is received by the linear motion guide device 60. If a lower portionof the linear motion guide device 60 is not supported even when thelinear motion guide device 60 is highly rigid, bending occurs andaffects the tilting of the lens shift unit 3. Namely, this is becausethe bending of the linear motion guide device 60 whose lower portion isnot supported approximates bending of a beam, and the bending of thebeam (specifically, the bending of a both-end supported beam and thebending of a cantilevered beam) is calculated by taking the third powerof the length.

Therefore, in the present embodiment, as shown in FIG. 6, thearrangement of the first linear motion guide device 60A and the secondlinear motion guide device 60B in the first lens guide unit 3Asupporting the lens shift unit 3 has been developed. Specifically, thefirst track rail 61A and the second track rail 61B are disposed tointersect each other in the two orthogonal axis directions along the Xaxis and the Y axis. The first slider block 62A and the second sliderblock 62B which are respectively mounted to be relatively movable on thefirst track rail 61A and the second track rail 61B are disposed to atleast partially overlap each other in the Z axis direction orthogonal tothe two orthogonal axis directions. Since each of the first slider block62A and the second slider block 62B is the portion that receives a load,the first slider block 62A and the second slider block 62B at leastpartially overlap each other in the Z axis direction, whereby a lowerportion of the portion of the linear motion guide device 60 thatreceives the load is supported so that the bending of the linear motionguide device 60 is reduced. In this manner, the bending of the framesection 20 is also reduced and the tilting of the lens shift unit 3 isinhibited.

In the present embodiment, as shown in FIG. 8, the first slider block62A and the second slider block 62B are relatively movable within therange in which the first slider block 62A and the second slider block62B at least partially overlap each other in the Z axis direction.According to this configuration, when the linear motion guide device 60constituting the first lens guide unit 3A is viewed from the Z axisdirection, the first slider block 62A and the second slider block 62Balways overlap each other at any position in the movable range R1 andthe movable range R2. For this reason, the bending of the frame section20 between the first slider block 62A and the second slider block 62Bcan be minimized so that the bending of the linear motion guide device60 can also be minimized.

In the present embodiment, as shown in FIG. 6, the first slider block62A has the plurality of fixing holes 70 for fixing the saddle member22, and the second track rail 61B has the plurality of fixing holes 66for fixing the second track rail 61B to the saddle member 22. Theplurality of fixing holes 70 of the first slider block 62A are disposedalternately with the plurality of fixing holes 66 of the second trackrail 61B along the second track rail 61B when viewed in the Z axisdirection. According to this configuration, as shown in FIG. 7, thefirst slider block 62A can be fixed immediately below the second trackrail 61B which is a strength member. As a result, since the position ofthe first slider block 62A that receives the load does not separate fromthe second track rail 61B, the bending of the frame section 20 and thelinear motion guide device 60 can be inhibited.

In the present embodiment, as shown in FIGS. 1 and 2, the first lensguide unit 3A supports the lens mount 2 via the second lens guide unit3B which guides the lens mount 2 in the Z axis direction. For thisreason, it is possible to accurately guide the lens mount 2 in the threeorthogonal axis directions in a state in which the bending of the lensshift unit 3 is inhibited.

In the present embodiment, since the first slider block 62A and thesecond slider block 62B are disposed to overlap each other in thevertical direction (Z axis direction), not only the bending due to theload of the lens 100, but also the bending due to the weight of the lensmoving mechanism 1 can be suitably inhibited.

As described above, the aforementioned lens moving mechanism 1 of thepresent embodiment includes the lens mount 2 on which the lens 100 forprojecting light is mounted, and the first lens guide unit 3A whichsupports the lens mount 2 and guides the lens mount 2 in the twoorthogonal axis directions among the three orthogonal axis directionsincluding the optical axis direction of the light. The first lens guideunit 3A includes the first track rail 61A and the second track rail 61Bwhich are disposed to intersect each other in the two orthogonal axisdirections, and the first slider block 62A and the second slider block62B which are mounted to be relatively movable on both or each of thefirst track rail 61A and the second track rail 61B. The first sliderblock 62A and the second slider block 62B at least partially overlapeach other in the Z axis direction orthogonal to the two orthogonal axisdirections. By adopting this configuration, the occurrence of bendingcan be inhibited and a lightweight and highly rigid lens movingmechanism 1 can be obtained.

As described above, although a suitable embodiment of the presentinvention has been described with reference to the drawings, the presentinvention is not limited to the above-mentioned embodiment. It should beunderstood that the shapes, combinations, and the like of theconstituent members shown in the above-described embodiment are merelyexamples, and various changes can be made based on design requirementsand the like without departing from the spirit of the present invention.

For example, the embodiment of the present invention may employ modifiedexamples shown in FIGS. 10 to 12 below. In the following description,the same or equivalent components as or to those of the embodimentdescribed above are designated by the same reference numerals, and thedescription thereof will be simplified or omitted.

FIG. 10 is a plan view showing the relationship between the movablerange R1 of the first slider block 62A and the movable range R2 of thesecond slider block 62B according to a modified example of theembodiment of the present invention.

The first slider block 62A shown in FIG. 10 has a rectangular shapeelongated in the longitudinal direction of the first track rail 61A. Thesecond slider block 62B has a rectangular shape elongated in thelongitudinal direction of the second track rail 61B. In addition, thefirst slider block 62A and the second slider block 62B are relativelymovable within a range in which the overlapping area S in the Z axisdirection (one axis direction) does not change. According to thisconfiguration, when the linear motion guide device 60 constituting thefirst lens guide unit 3A is viewed in the Z axis direction, the firstslider block 62A and the second slider block 62B are disposed to overlapeach other always in the same area S at any position in the movablerange R1 and the movable range R2. For this reason, there is no changein the bending of the frame section 20 between the first slider block62A and the second slider block 62B, and it is also possible to inhibita change in the bending of the linear motion guide device 60.

FIG. 11 is a perspective view showing an arrangement of the linearmotion guide device 60 in the first lens guide unit 3A according to amodified example of the embodiment of the present invention.

A linear motion guide device 60D shown in FIG. 11 includes a sliderblock 62D mounted to be relatively movable on both of the first trackrail 61A and the second track rail 61B. The slider block 62D has aconfiguration in which the first slider block 62A and the second sliderblock 62B described above are combined, and includes rail accommodationgrooves 69 at the top and bottom. According to this configuration, theslider block 62D is always disposed at the intersecting portion of thefirst track rail 61A and the second track rail 61B in the Z axisdirection. Also, there is an advantage that the saddle member 22 is notrequired.

On the other hand, as shown in FIG. 4, the first lens guide unit 3A ofthe above-described embodiment includes the table member 23 supportingthe lens mount 2, the saddle member 22 to which the second track rail61B is fixed and which supports the table member 23 via the secondslider block 62B, and the base member 21 to which the first track rail61A is fixed and which supports the saddle member 22 via the firstslider block 62A and is fixed to the projector main body 102. Accordingto this configuration, the lens mount 2 can be guided in the twoorthogonal axis directions without using the linear motion guide device60D having a complicated configuration shown in FIG. 11. Also, in thisconfiguration, although the number of installed linear motion guidedevices 60 is increased, the configuration is simple, which isadvantageous in cost, accordingly.

FIG. 12 is a plan view showing a base member 21 according to a modifiedexample of the embodiment of the present invention.

The fixing holes 21 a of the base member 21 shown in FIG. 12 aredisposed inside of the pair of first linear motion guide devices 60Adisposed at intervals in the optical axis direction. According to thisconfiguration, the distance between the fixing holes 21 a is smaller(closer) than the distance between the fixing holes 21 a shown in FIG.5, and thus the bending of the base member 21 becomes smaller. Forexample, when the lens moving mechanism 1 is suspended from a ceiling,by reducing the distance between the fixing holes 21 a, the bending ofthe base member 21 between the fixing holes 21 a becomes smaller.

In the above embodiment, the fixing holes 21 a of the base member 21 hasbeen disposed in the vicinity of the first slider block 62A. However,the fixing holes 21 a of the base member 21 may be disposed, forexample, immediately below the first track rail 61A or the first sliderblock 62A and be bolted from the back side of the base member 21. Thefixing holes 21 a may be disposed immediately below the fixing holes 66of the first track rail 61A, and both of the first track rail 61A andthe base member 21 may be fixed to the projector main body 102 by thebolts 80.

In the above embodiment, the configuration in which the reinforcingportion 27 is provided on the table member 23 has been adopted. However,for example, when the track rails 61 fixed coaxially in the base member21 and the saddle member 22 are disposed at intervals, the reinforcingportion 27 may be provided in the interval.

In the above embodiment, although balls are used as rolling elements,other rolling elements such as rollers may be used, for example.

INDUSTRIAL APPLICABILITY

The occurrence of bending can be inhibited, and a lightweight and highlyrigid lens moving mechanism can be obtained.

REFERENCE SIGNS LIST

1 Lens moving mechanism

2 Lens mount (lens mount unit)

3A First lens guide unit (lens guide unit)

3B Second lens guide unit

21 Base member (fixing member)

22 Saddle member (intermediate member)

23 Table member (support member)

61A First track rail (first track body)

61B Second track rail (second track body)

62A First slider block (first moving body)

62B Second slider block (second moving body)

62D Slider block (moving body)

66 Fixing hole (track body fixing hole)

70 Fixing hole (moving body fixing hole)

100 Lens

101 Optical axis

102 Projector main body (mounting object)

R1 Movable range

R2 Movable range

S Area

1. A lens moving mechanism comprising: a lens mount unit on which a lensfor projecting light is mounted; and a lens guide unit which supportsthe lens mount unit and guides the lens mount unit in two orthogonalaxis directions among the three orthogonal axis directions including anoptical axis direction of the light; wherein the lens guide unitincluding a first track body and a second track body which are disposedto intersect each other in the two orthogonal axis directions, and oneor a plurality of moving bodies which are mounted to be relativelymovable on both or each of the first track body and the second trackbody via rolling elements, the moving bodies which form a load rollingelement rolling path for the rolling elements on both sides in a widthdirection of the first track body and the second track body, and the oneor plurality of moving bodies are disposed at an intersecting portionbetween the first track body and the second track body in one axisdirection orthogonal to the two orthogonal axis directions, or aredisposed to at least partially overlap each other in the one axisdirection.
 2. The lens moving mechanism according to claim 1, whereinthe lens guide unit includes a first moving body mounted to berelatively movable along the first track body; and a second moving bodymounted to be relatively movable along the second track body, and thefirst moving body and the second moving body are relatively movablewithin a range in which the first moving body and the second moving bodyat least partially overlap each other in the one axis direction.
 3. Thelens moving mechanism according to claim 2, wherein the first movingbody and the second moving body are relatively movable within a range inwhich an overlapping area in the one axis direction does not change. 4.The lens moving mechanism according to claim 2, wherein the lens guideunit includes: a support member which supports the lens mount unit; anintermediate member to which the second track body is fixed, and whichsupports the support member via the second moving body; and a fixingmember to which the first track body is fixed, and which supports theintermediate member via the first moving body and is fixed to a mountingobject.
 5. The lens moving mechanism according to claim 4, wherein thefirst moving body, the second moving body, the first track body, and thesecond track body have a larger Young's modulus than those of thesupport member, the intermediate member, and the fixing member.
 6. Thelens moving mechanism according to claim 4, wherein the first movingbody has a plurality of moving body fixing holes for fixing theintermediate member, the second track body has a plurality of track bodyfixing holes for fixing the second track body to the intermediatemember, and the plurality of moving body fixing holes of the firstmoving body are disposed alternately with the plurality of track bodyfixing holes of the second track body along the second track body whenviewed in the one axis direction.
 7. The lens moving mechanism accordingto claim 1, wherein the lens guide unit supports the lens mount unit viaa second lens guide unit which guides the lens mount unit in the oneaxis direction.
 8. The lens moving mechanism according to claim 1,wherein the one axis direction is a vertical direction.